Method of treating fresh meats



United States Patent 24,992 METHOD OF TREATING FRESH MEATS Ernest E.Ellies, Wilmette, lll., assignor to Tee-Pak, luc., Chicago, 11]., acorporation of Illinois No Drawing. Original No. 2,847,313, dated Aug.12, 1958, Ser. No. 550,513, Dec. 1, 1955. Application for reissue Aug.11, 1960, Ser. No. 49,112

8 Claims. (Cl. 99-174) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

This invention relates to the treatment of meat and more particularly,to a method for producing and handling comminuted meat which permits asubstantial time lapse to occur between the comminution and the finaldisplay of the meat to the ultimate purchaser, without any substantialimpairment or loss of the incipient attractive red color and bloomoriginally possessed by the meat.

The loss of bloom and the undesirable changes in color which meatundergoes with the passage of time are well known and are typically andparticularly evident in the case of comminuted meats, such as beefhamburger, which turns bright red shortly after being ground, and then,Within a relatively few hours gradually loses this red bloom and becomesless and less attractive.

This undesirable characteristic of meat presents a number of seriousproblems to the meat merchandiser, as will be illustrated below. Forexample, in most areas Friday and Saturday are the busiest days of theweek for a meat retailer, and in preparing for these periods the butcherordinarily tries to have as much of the meat chopping, cutting, grindingand so on done in advance so that there will be a minimum of such meatprocessing to be performed on those busy days. It would appear, at firstblush, that one of the operations that the butcher himself could andshould perform well in advance of the display for sale thereof, would bethe grinding up of beef for hamburger. Unfortunately, it has been foundand the fact is well known as aforesaid, that hamburger undergoes arapid, deleterious, irreversible color change with the passage of timeand that meat ground on say Thursday night no longer possesses asreadily sa able a picture of an eye-appealing product on Saturdaymoming, as does meat ground on Saturday morning.

The problem is likewise a serious one in the case of meat merchandisingorganizations of the type wherein the bulk of the meat chopping,cutting, grinding and the like is done in a more or less centrallylocated establishment and the prepared meats, cut, ground and packaged,are transported by trucks to self-service branch stores. In the lattercase the present inability to deliver ground beef to a retail store, saya number of days in advance of the sale thereof to the purchaser(without the product losing much of its attractive color and appearancein the interim) presents quite a merchandising problem, and one notsatisfactorily solved until the present invention.

Referring to the color changes, loss of bloom and the like which occurin meats after they have been cut, sliced, or ground, it is believedthat the various pigments present in meat are effected, color-wise by anumber of factors such as the concentration of oxygen in the immediatearea of the meat, whether the meat is refrigerated or not, the rate atwhich transpiration occurs through any covering or wrapping medium thatmay be placed on or over the meat and the permeability of any suchcovering or wrapping if any, to oxygen, In any event and whatever thereasons, the phenomena associated with the color changes which occur inmeat appear to involve a number of inter-related, obscure, and complexfactors.

Thus far, there has been no completely satisfactory technique by whichmeat, especially comminuted meat, could be stored for commerciallyimportant periods of time without loss of the color and bloom whichcharacterizes the fresh appearance of say ground beef at its best.

I have discovered a novel method and means by which a comminuted meatproduct especially ground beef, beef trimmings, stew beef or beefchunks, can be produced and handled without losing its incipientattractive color, bloom, appearance and eye appeal even though the meatmay have been comminuted up to several days or longer in advance of itsdisplay for sale purposes. in other words, my new process makes itpossible for the meat merchandiser to comminute beef for hamburger, orto prepare stew beef, beef chunks, beef trimmings and the like even daysahead of a time when it is to be retailed without loss of its incipientor dormant attractive appearance and desirable organoleptic properties.

In general my novel method involves placing freshly ground meat whetherit be in relatively finely comminuted form like hamburger or in the formof coarser particles such as stew beef, beef chunks, beef trimmings andthe like, into a tube, bag, pouch, envelope or the like, which may beclosed in any one, or a combination of several ways to form an air-tightpackage the bag or the like being composed of a flexible film materialhaving a predetermined oxygen permeability, and which also has,preferably, certain permeability characteristics with respect tomoisturevapor, nitrogen and carbon dioxide, maintaining the thus encasedor packaged meat preferably at refrigerator temperatures, and then,removing the meat from the package shortly prior to display, sale. orpreparation for consumption. The meat, on removal from the package, willbe found to either have or quickly assume or develop the same or even agreater degree of brightness in color, bloom and appearance, as thatwhich would have developed shortly after its comminution, if suchdevelopment had not been arrested by enveloping the meat in said bag.Consumer-size packages are, of course, included, in which case it is thehousewife who removes the packaging material from the meat, at home, andpermits the incipient bloom to develop there.

It is essential in the practice of my invention that the meat be placedin the aforesaid bag, envelope, tube, or the like as soon as possibleafter it has been comminuted, and in any event before there has beendevelopment of full bloom on the surfaces of the comminuted meat. Thistime-period can readily be determined since when meat, especially beef,is first out the surface is purplish in color due, it is thought to thepresence of reduced hemoglobin. The bright red color which follows thepurplish hue first visible after meat is first comminuted or chopped isunmistakable. As pointed out before the meat must be encased within thebag, envelope, tube or pouch as soon as possible after grinding butunder no circumstances after it has reached its full bloom, whichnormally occurs 15 to 30 minutes after grinding. Preferably, thecontainer is filled and the open end or ends sealed, tied or clipped tomake it air-tight."

The nature of the bag, envelope, tube, pouch or the like into which themeat, freshly comrninuted, is placed is highly important. In the firstplace, the container must be formed of a flexible film material or alaminate of flexible film materials, and it must have an oxygenpermeability ranging from 0.01 X 10- to 1.0x 10- and preferably from0.01 X 10- to 0.1x 10- cc.-mm./sec./ cmfi/cm. Hg at 30 C., as determinedby the techniques referred to in the Journal of Polymer Science 16,89-91 (1955). Most desirably, the packages are formed from a laminate oftwo or more films which may, for example, be produced in accordance withthe procedure referred to with respect to multiply saran film packagesin U.S. Patent Nos. 2,679,968 and 2,679,969

The moisture-vapor permeability of saran, one of the preferred materialsused in my invention, may be from about 0.40 to [).6O 10i gm.-cm./sq.cm./24 hr. These values were obtained using Payne permeability cupscontaining anhydrous calcium chloride. The cups were kept in theisothermal cabinet for nine days at 33 C. and 60 percent relativehumidity. The nitrogen and carbon dioxide permeability values of saranas listed in the Journal of Polymer Science 16, 89-91 (1955) were 0.C094 1O and 019x10 cc./mm./sec. cm. /cm. Hg at 30 C.

The films may be printed or unprinted, and may have printing between thefilm layers if desired; and the film may be in clear transparent form ormay contain filters, dyes, and additives of one kind or another.Adhesives may also be used if desired.

Freshly comminuted meat, when encased or enveloped in a package formedeither of single layer or more desirably of multi-ply films made of acopolymer of vinylidene chloride and vinyl chloride, commonly known assaran, or similar film, may be kept at ordinary refrigerationtemperatures without loss of its color and bloom properties for a periodof time far in excess of the time within which the meat, even whenencased in cellophane or What is known in the trade as fibrous casing orother packaging materials not having the requisite per meability orother characteristics, turns gray and loses its bloom and its otherdesired properties.

My discovery is totally unexpected in view of the com monly acceptedbelief that a wrapping or packaging film in order for the meat to beideally packaged insofar as color preservation is concerned, should beof the type which has a high oxygen permeability, unlike the flexiblefilm materials required in the practice of my invention.

I have found, in sharp contrast to such widely held views, that used inaccordance with my aforesaid method, a film which has low oxygenpermeability, such as saran, is surprisingly effective and makespossible for the first time a commercially practical method forproducing and handling comminuted meat to meet the numerous exigencieswhich are intimately associated with the successful merchandising ofsuch a product.

Specific illustrations of the practice and efficacy of my invention aredescribed hereinafter. The described tests point out comparative resultsobtained particularly with different packaging materials used andillustrate variations in the quality of the hamburger which occur whenprocessed in saran over that processed in other films or types of films.

Specifically, ground beef was packaged in a variety of packagingmaterials including a moisture proof" type of cellophane known ascellophane MSAT 80, the nonwoven cellulosic product known in the tradeas fibrous casing," saran, a coated regenerated cellulose casing knownas CMVP produced in accordance with the teachings of U.S. Patents2,627,471 and 2,627,483, and fibrous casing which had been coated withsaran. Tubes of these materials filled with ground beef were stored in arefrigerator held at a temperature of 45 F., plus or minus 3 F., at arelative humidity of 8085%. The beef had a fat content of approximately40%, and immediately after grinding was stuffed into tubes of the abovepackaging materials, each tube having a capacity of about 1 to 1%pounds.

All of the tubes were securely tied with a cord on both ends to make thepackage air-tight. Sampling of the product was done on the second,fourth and eighth days of storage and included specifically sampling forthe purpose of microbial evaluations, and organoleptic evaluationsincluding color, odor and flavor. Cooked samples, after storage werealso prepared and tested.

4 All of the containers showed some change in weight due to moistureloss, the loss being most severe with the hamburger which was packagedin the fibrous casing, in which the moisture loss was 11.8% after 4 daysof storage and progressed to 16.2% after an eight day storage period.The CMVP product showed somewhat better moisture retention properties,but the rate of moisture loss was still significant being 5.8% afterfour days of storage and 10.4% after an eight day storage period.

Moisture loss in the case of the saran packaged product and the sarancoated fibrous product was significantly lower than that of theforegoing products.

The film bacterial count was substantially lower for the saran packagedmeat and for the saran coated fibrous product compared to the others.

It was found surprisingly that on inspection of the surface and interiorof the hamburger for yeast counts, that not only did the yeastpopulation tend to gradually increase with storage time, which wasexpected, but that the hamburger contained in the saran or saran-coatedfibrous casing had an unaccountably, and significantly, lower yeastcount than hamburger packaged in the other materials.

At the eighth day of the storage period all of the hamburger, with theexception of that in the saran tube was objectionable on sight. The meatin the saran coated fibrous casing had a dull brownish grey color. Thehamber container in the fibrous casing" was a very dark reddish purplehaving a desiccated appearance. So did that in the CMVP.

In sharp contrast to the foregoing it was found that the hamburgerpackaged in the saran tube had an outstandingly excellent pinkappearance throughout the storage period, and that unlike the hamburgerpackaged in the other films, when the hamburger was removed from thesaran package, after a few seconds exposure to the air it assumed anattractive bright red color. Furthermore, the flavor and odor of thehamburger packaged in the saran tube was superior on the basis of blindtesting to the others.

While the preferred film for use in practicing my invention is saran,i.e. a copolymer of vinylidene chloride and vinyl chloride other filmsor film combinations e.g. laminates, having similar physicalcharacteristics, especially oxygen permeability may be used, as forexample laminates of saran with itself, with Pliofilm, vinyl,polystyrene, and other multi-ply saran-containing laminates described inU.S. Patent No. 2,679,969, whether secured together by adhesives or bytheir inherent cling. Furthermore, films coated with saran latex, e.g.polyethylene coated with saran may also be used.

By my invention I have now made it possible, and in a practicalcommercial, economical way to provide at the retail-level particularly,attractive comminuted beef having a characteristic fresh" appearance, incontrast to the dull. lifeless, dark brown appearance which ground beefordinarily assumes on storage, without the absolute requirement ofgrinding the beef immediately before display. This results in not onlyoffering a more attractive product to the housewife, but is a realadvantage to the meat merchandiser to whom the present invention givesan important degree of flexibility in operation.

It will be understood that the foregoing is presented for purpose ofillustration only and that the invention is not to be limited to anydetails or steps except as is required by the claims, since it will beobvious to those skilled in the art that certain advantages in thedetails and steps are contemplated by the present invention.

I claim:

1. A method for controlling the development of the incipient bloom.color and organoleptic characteristics of comminuted fresh meats whichcomprises enclosing comminuted fresh meat within about 30 minutes aftercomrninution in a film material which has a permeability of oxygenthrough said film ranging from about 0.01X10- to 1.0Xl0cc.-mrn./sec./cm. /cm. Hg at 30 C., a moisture vapor permeability offrom about 0.4OXlO- to 0.6() l0 gm.cm./sq. cm./24 hrs, determined at 33C. and 60% relative humidity, maintaining the said comminuted meat inthe said film material chilled for a period in excess of that at whichunwrapped meat loses a significant part of its red color aftercomminution, removing the said meat from its encasement in the said filmmaterial and mixing the said meat in contact with the atmosphere.

2. The method of claim 1 wherein the meat is beef.

3. The method of claim 1 wherein the film material is made of acopolymer of vinylidene chloride and vinyl chloride.

4. The method of claim 1 wherein the meat is comminuted beef and thefilm material is a cooplymer of vinylidene chloride and vinyl chloride.

5. A method for controlling the development of the incipient bloom,color and organoleptic characteristics of comminuted fresh meats whichcomprises enclosing comminuted fresh meat within about 30 minutes aftercomminution in a flexible film which has a permeability of oxygenthrough said film ranging from about 0.01 x10 to LOXIO-"cc.-mm./sec./cm. /cm. Hg, at 30 C., maintaining the said comminuted meatin the said film chilled for a period in excess of that at whichunwrapped fresh meat loses a significant part of its red color afterReferences Cited in the file of this patent or the original patentUNITED STATES PATENTS Rumsey Mar. 13, 1951 Richter June 1, 1954 OTHERREFERENCES Modern Packaging, January 1949, pp. 134 to 137, inclusive,article entitled Meat-Film Considerations by Nelson Allen.

Modern Packaging, September 1951, pp. 122, 123, 174, and 177, articleentitled Meat-Wrapping Technique by Thomas H. Derby.

Food Technology, April 1955, pp. 194, 195, and 196, article entitledDiscoloration of Fresh Red Meat and Its Relationship to Film OxygenPermeability.

Dedication Rvissuc Tin. QIDOl-Jfinest E. Ellz'ns, \Vilmvttv. Ill. MET.iOD OF TREAT- ING FRESH MEATS. Palvnt clutlwl my 230, 19(51. DLHUWIUOHfiled Um: 1h. 19H. by Hm zlfisignvu, Ten-151k. [mt Hereby (lmliuutes tothe Public all of the turm of said mlvnt suhsvquvnt to Oct. 2:;, 1074.

[Official Gazette March 25, 1975.]

